Improved apparatus for regulating the draft and preventing the explosion of



UNITED STATES PATENT GEEICE.

II. L. JUSTICE, OF NASHVILLE, TENNESSEE.

IMPROVED APPARATUS FOR REGULATING THE DRAFT AND PREVENTING THE EXPLOSION OF STEAM-BOILERS.

Specification forming part of Letters Patent No. 28,675, dated June 12, 1860.

To @ZZ whom it may concern.-

Be it known that I, H. L. JUSTICE, of Nashville, in the county of Davidson, in the State of Tennessee, have invented a new and Improved Mode of Preventing Steam-Boilers from Bursting, and at the same time saving steam and fuel; and I do hereby declare that the following is a full, and exact description thereof7 reference being had to the accompanying drawings, and to the letters of reference marked thereon.

The nature of my invention consists in providing the upperpart of a steam-boiler with a small cylinder with its properly-packed piston acted upon with full force by the steam; but this piston is checked by a spring or springs and connected with arms and rods acting upon the fire-draft doors and smoke-valve, and also act at higher pressure on an inside valve, permitting the steam to escape, thus preventing all danger and saving fuel, regulating itself without aid or risk.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

I construct my steam-boiler in any of the known forms, and may apply to it gage-cocks and other appendages of such boilers; but in order to obviate the dangers arising from the nature of steam and the imperfect safetyvalves now in use I attach to the upper part of the boiler a cylinder, (represented on the drawings by letter A in Figures I and IIII.)

Fig. I is a longitudinal section of the cylinder and its appendages, and illustrated as follows by letters Inarked thereon: B is the piston-head; C, piston; D, screws to regulate the springs, and E a shoulder on the piston above thehead to support the spring orsprings. F and F represent the springs which control the pressure of the steam when properly regulated by the screws D D. Gis an angular lever connecting the motion from the piston to the flue-doors and butterfly-valve Q. II is an arm or lever, which when raised presses in the valve-piston I on the inverted valve K below the piston-head.

Fig. III is a plan view of the cylinder A and its different parts. M is a piece (which Iwill call a stirrup) attached to the lever H, by

which stirrup this lever is raised when the shoulder e of the piston-rod is forced up against it by the steam-pressure. (See Fig. II.)

Fig. II is a side elevation'. -M is the abovenamed stirrup; e, the shoulder; N N, iiutes or grooves on the sides of the valve-piston I,which allow the free escape of steam when the valve K is opened.

Fig. IIII is a side elevation of the boiler with my eontrivance attached to it. O is the boiler; T, the iire-flue or draft-flue which passes through the boiler; S, the chimney, breeching, or smoke-stack; U, the flue-door, made in shape of a butterfly-valve; Q, the butterfly-valve in the smoke-flue or chimney. L, P, and P are jointed rods and levers connected with the angular piston-lever G and communicating its motion to the flue-doors and butterfly-damper. When, therefore, the steam should happen to rise above the desired pressure, it will overcome the resistance of the springs and push up the piston. The latter acts on the lever Gr, this on the rods L and P, and these by P on the valves U and Q, opening the former and closing the latter, thereby checking the draft and dampening the nre. The steam will then soon subside, when the spring will force back the piston to its original or lower position, the draft-valves will again be closed, and the chimney-valve again open, by which the fire will be restored to proper heat; but should accidentally this dampening of the fire not have the quick action upon the pressure of steam as expected or wanted and the piston be forced up with great power it will raise the lever H by raising the stirrup attached to it, and this lever will instantly open the inverted valve K below the piston-head and allow the steam to escape through the grooves N N, Fig. II. Thus with steam-valve open and slack res any one will understand that all danger is preventedthat is, of explosion; but it will plainly be seen, also, that this immediate action of the steam on the draft-that is, on the fire, and the reverse or the action of the ire in consequence of the draft on the generation of steam and its high or low pressure-will not only keep a uniform pressure in the boiler-a great desideratum-but it also will save fuel to a great extent, because When the iires get too brisk it will keep them back, instead of, as usual, Wasting` steam and consuming' fuel.

I deem it needless to further argue the greatimportance and value of this simple and complete invention, Which is too plain to not be appreciated by mcnwho understand this kind of machinery and by all who have life and body, kin, friends, and property at stake on the safety of steam-boilers, when the saving' of fuel itself is a qualiiication of this invention to make its adoption an object.

Of course I do not claim the damper or the Hue-doors, nor a cylinder with its piston or springs for regulating steam-pressure, for I am aware of their previous use.

H. L. JUSTICE. Witnesses:

R. A. NATHURST, IVM. I-I. HAGANs. 

